$OpenBSD: patch-src_bin_showexternal,v 1.1 2012/03/17 10:57:23 sthen Exp $
--- src/bin/showexternal.orig	Tue Feb  8 16:39:05 1994
+++ src/bin/showexternal	Sat Mar 17 10:51:52 2012
@@ -15,9 +15,45 @@
 # WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES.
 # 
 
+# Check argument integrity. Don't trust mail headers
+switch ("$1$2$3$4$5$6$7")
+case "*[\t ]*":
+  echo "Illegal white space in arguments\!"
+  echo "Command was:"
+  echo "'$0' '$1' '$2' '$3' '$4' '$5' '$6' '$7'"
+  exit 2
+endsw
+
 onintr cleanup
+# Set a sensible value for the temporary directory, if its not
+# already set.  If TMPDIR is set previously, then we will
+# assume it is adequately protected.
 if (! $?METAMAIL_TMPDIR) then
-    set METAMAIL_TMPDIR=/tmp
+    if ($?TMPDIR) then
+        set METAMAIL_TMPDIR="$TMPDIR"
+    else
+        set METAMAIL_TMPDIR=~/metamail_tmp
+    endif
+endif
+
+# Set a sensible umask value
+umask 077
+
+# Make sure that the temporary directory is available
+if (! -d "$METAMAIL_TMPDIR") then
+
+    if (! -e "$METAMAIL_TMPDIR") then
+        mkdir "$METAMAIL_TMPDIR"
+    else
+        echo "$METAMAIL_TMPDIR exists, but is not a directory"
+        exit 2
+    endif
+
+    if ( $status != 0 || ! -d "$METAMAIL_TMPDIR" ) then
+        echo "Error creating $METAMAIL_TMPDIR"
+        exit 2
+    endif
+
 endif
 if (! $?FTP) then
     set FTP=ftp
